Friday, July 3, 2009

Effect of SPAM (spinal posteroanterior mobilization) in asymptomatic subjects

SPAM includes commonly applied forces of low-frequency sinusoidal oscillations (<2 Hz) as used in mobilization. Despite the reliance on these techniques in clinical practice, there is little scientific evidence to substantiate their use. Before progress in this area can be made, it is necessary to characterize the forces used during typical mobilization procedures.

Spinal mobilization is usually applied to
1. modulates pain
2. improve mobility of a stiff segment
3. finally, to assess the condition

However these benefits are marked in the subject suffering from mechanical spine disorders. Fundamental to this concept is the belief that spinal mobilization will influence the mechanical properties of the symptomatic motion segment. Nothing is known about what are the effects of SPAM in asymptomatic subjects.

Using proper control methods trained physiotherapist applied the standardized PA mobilization technique to L1, L3 & L5 spinous process for two minutes. The mean force of 146 N (standard deviation = 8 N) at a frequency of 1.5 Hz was applied. It was found that SPAM has no segmental effect on spinal PA stiffness (1).

Discussion: This paper of Allison & colleagues questions “Which mechanisms contribute to the changes that occur after PA spinal mobilization?” However Nathan & colleagues in 1994 found low force, PA impulses produce measurable segmental motions and reinforce the notion that mechanical processes play an important role in spinal manipulation and mobilization.


1. Allison G et al; Physiother Res Int. 2001;6(3):145-56.

2. Nathan M et al; J Manipulative Physiol Ther. 1994 Sep;17(7):431-41.

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